Manufacture of watch-balances



(No Model.) 2 Sheets-Sheet 1.

G. E. HUNTER.

MANUFACTURE OF WATCH BALANCES.

' N07 347,271. Patented Aug. 10, 1886.

2 Sheets-Sheet 2.

(No Model.)

G.E.H UNTER. MANUPAGTURB 0P WATGH BALANGES.

No, 347,271. Patented Aug. 10, 1886.

' PETERS. PhawLixho m hur, Washington. DJ;

UNITED STATEs GEORGE E. HUNTER,

PATENT rrrcno OF 'ELGIN, ASSIGIN OR TO THE ELGIN NATIONAL \VATOHCOMPANY, OF CHICAGO, ILLINOIS.

MANUFACTURE OF WATCH-BALANCES.

SPEQIIICATIQN forming part of Letters Patent No. 347,271, dated August10, 1886.

Application filed March 4,1386. Serial No.194,005. (N'o model.)

To all whom it may concern:

Be it known that I, GEORGE E. HUNTER, of Elgin, in the county of Kane,and in the State of Illinois, have invented certain new and usefulImprovementsin \Vatch-Balances; and I do hereby declare that thefollowing is a full, clear, and exact description thereof, referencebeing had to the accompanying drawings, in which- Figure 1 is aperspective view of the steel and brass parts of the rim-blank beforebeing united. Fig. 2is alikeviewof the same when joined together. Fig. 3is a perspective view of said rim-blank dressed to size and prepared I 5for the reception of peripheral adj usting screws. Fig. 4 is a like viewof a rim cut to length and bent to shape. Fig. 5 is a perspective viewof the central portion or spider of the balancewheel. Fig. 6 isa likeview ofthe completed wheel, and Fig. 7 is a section of said wheelthrough the plane of its vibration. Letters of like name and kind referto like parts in each of the figures.

In the construction of watch balances it has heretofore been customaryto make the arm and the steel portion of the rim from one solid piece ofmetal by turning the same into the form of adisk having the desireddiameter, then brazing upon its periphery a ring of brass, then turningwithin one face of said steel disk a recess which in diametercorrespondsto the interior diameter of the balance-rim and in depth to thethickness of said rim, less the thickness of the balance-arm, thenpunching 3 5 from the recessed portion of said disk the surplus metal,so as to leave said arm and rim, then drilling and tapping within saidrim the necessary radial holes for the adjustingscrews, then cuttingsaid rim at two opposite points, and, lastly, giving to said divided rima true circular form. This method of construction is, however,expensive, and the product very inaccurate, as the metalscomposing thebalance-rim do not have uniform thickness either jointly or severallythroughout their length, and, consequently, there is such unequalexpansion and contraction of said rim as to render it impracticable toproperly poise the balance forthe ordinary variations in temperature.

The design of my invention is to lessen the cost, to simplify theconstruction, and to increase the efficiency of watch-balances; and tothis end said invention consists in the method employed,substantially asand for the purpose hereinafter specified.

In the carrying ofmy invention into practice a strip of steel, a, havingany desired length is drawn through or between polished dies or rollersuntil it has a uniform thickness, substantially such as is required forthe rim of the finished balance, but is slightly greater in width thansuch rim, Upon one side of the steel strip ais now brazed a strip ofbrass, a,

which corresponds therewith in length and 6:;

width, but has a slightly greater thickness than is desired in thefinished rim, care being taken that said stri s coincide throughouttheir length, after which the compound strip A is passed through orbetween spring-pressed 7o rollers or dies, which operate to compress thebrass portion a equally throughout its length. The strip A will usuallyhave such length as to enable several balance-rims to be constructedfrom it, in which event, before said strip is out 7 into the requiredlengths, the necessary openings,a'",for dowel-pins or rivets, and foradj usting-screws,are drilled at predetermined relative points, and saidscrew-openings tapped, after which it is passed between mills thatoperate upon its edges and upon the exposed side of the brass part a,and give to said strip substantially the required transverse dimensions.The compound strip A is now passed between burnishing dies or rollers,which op crate to finish its exposed surfaces, and at the same timeremove any unevenness in thickness which may have resulted from the preceding operations. The brass portion a being the softer metal, theaction of said dies or 0 rollers causes the same to accurately conformto the steel portion a, by which means said parts have jointly andseverally a uniform thickness throughout their length, and the grains ofthe metals are arranged lengthwise 9 5 of the same in parallel lines.The compound strip A, thus constructed, is now out into suitablelengths, and each piece then completed by being passed between polishedrollers, which give to the same the proper curvature.

Thewheel-spider or cross-bar B is preferably made by dies from a stripof steel having suf- IOO ficient width, and at each end of the same isformed a lug, I), that is turned upward at a right angle to said bar,and has a length equal to about twice the width of the same at suchpoint. The outer face of each lug is formed upon a curved line, and toit is secured one end of one of the curved rim-bars by means of a screw,0, aml one or more rivets or dowelpins, 0, which pass radially throughthe intersecting parts. Said screw projects beyond the periphery, and isthreaded; and upon such projecting portion is placed a nut, D, whichcorresponds in general size and shape to the like features of the headsof adjustingscrews that are placed within the threaded openings (6between said nut and the free end of said rim-bar. Said nut ispreferably split from one end nearly to its opposite end, and such splitportion given a slight inward spring, so as to cause it to grasp itsscrew with sufficient firmness to prevent accidental movement thereon.

Having thus described my invention, what I claim is- 1. As animprovement in the construction of watclrbalances, the method employedfor forming the rim -sections, which consists in combining two straightbars of steel and brass by brazing, and then giving to the compound barthe required curvature by means of rollers, substantially as and forthepurpose specified.

2. As an improvement in the construction of watch-balances, the methodof forming the rim-sections, which consists in brazing to gether twobars of steel and brass, and then compressing the brass between rollersuntil it has the required density, substantially as and for the purposeshown.

3. As an improvement in the construction of watch-balances, the methodemployed for forming the rim-sections,which consists, first, in unitingby brazing twostraight bars of steel and brass, next forming in suchcompound bar threaded openings for the reception of adjustingscrews,and, lastly, passing said bar through or between rollers and giving toit the required curved form, substantially as and for the purpose setforth.

4. The method employed for constructing watch-balances, which consistsin forming each ofthe rim-sections from straight bars of metal brazedtogether, then curving such eompou ml bar by rollers, and, lastly,securing one endot' said bar-section to or upon the central portion orspider, substantially as described.

5. The method employed for constructing watch-balances, which consists,first, in forming each of the rinrsections from straight bars of metalbrazed together, next in forming in such compound bar threaded openingsfor the reception of adjusting-screws, next in passing said bar throughor between rollers and giving to it a curved form, and, lastly, securingone ofits ends upon the spider of the wheel, substantially as specified.

In testimony that 1 claim the foregoing I have hereunto set my hand this28th day 01' December, 1885.

GEO. E. HUNTER.

.Vi tn esses:

\V. P. HEMMENs, W. H. CLOUDMAN.

